A violent past can lead to a violent future says child psychologist Guy Fowle.

He said those who were attacked at a young age sometimes end up with a repetition complex and try to re-write their personal history by switching roles.

Dr. Fowle, who has a clinic in Hamilton, said: "If they become the one who is then 'winning', the perpetrator instead of the victim, there is the illusion that they can get over the situation."

And aggressive role models can also be very dangerous for young minds.

"If you see people being violent then you are liable to copy, if the prevailing ethos is an eye for an eye, a tooth for a tooth.

"If that becomes the moral value of somebody that alone, without other factors, could make you a violent person."

Some personality types are naturally less prone to violence adaptable personality types, who can deal with change, will be less likely to get overly aggressive.

But the key question is how can society help those with violent tendencies stay calm and avoid conflict?

Dr. Fowle said controlling violent tendencies is best tackled by putting "feelings into words".

He explained: "For those who are not psychopaths if you put the feelings into words there is a delay, you therefore have a chance for another part of you to kick in, and realise that maybe violence is not the best option."

And verbal expression can help in other ways to diffuse the situation.

"When you put things into words you define what the problem is but also what it isn't."

It's a skill parents can teach children from an early age which should then be of help in later life. But the gang mentality also has a way of escalating violence — when a group-think takes over from an individual taking responsibility for his own actions.

In some ways the individual's identity becomes subsumed into the gang making backing down from a fight very risky for those not wanting to be cast out by their friends.

"In the context of gangs and shootings — it's the survival thing and who I am? They think 'If this is the way then so be it' instead of being the one not in the group and get hit upon by the others from their own gang."

So what can society do? Showing healthy alternatives to gang membership is one way.

New research shows that adverse experiences early in life can lead to minor childhood behaviour problems, which can grow into serious acts of teen violence, in a "cascading effect".

The November/December 2008 edition of the journal Child Development showed research done by a North Carolina psychologist who measured how violent behaviour develops across the lifespan, from early childhood through adolescence.

The study tracked 754 children from pre-school through adulthood and documented that children who have social and academic problems in elementary school are more likely to have parents who withdraw from them over time.

A Duke University summary wrote: "That opens the door for them to make friends with adolescents exhibiting deviant behaviours and, ultimately, leads them to engage in serious and sometimes costly acts of violence."

The path towards violence was largely the same for boys and girls, said Kenneth Dodge, the study leader and director of the Centre for Child and Family Policy at Duke University.

The cascade could be traced back to children born with biological risks or born into economically disadvantaged environments, both of which make consistent parenting a challenge.

The University's summary added: "They determined biological risk by assessing the temperaments of the children in infancy, based on mothers' reports; those at risk were irritable, easily startled and difficult to calm.

"These children are more likely to exhibit minor social and cognitive problems upon entering school." From there, the behaviour problems begin to "cascade," said Mr. Dodge.

But successful early intervention could redirect paths of anti-social development to prevent serious violent behaviour in adolescence, added Mr. Dodge.